抄録
Many bridges were washed away by the tsunami due to Great East Japan Earthquake. The authors firstly summarized that the tsunami in Tohoku Region mainly showed a steady flow shape, from the video and the photo recording the tsunami along Kesen River. Besides, 1~2m small waves were found at the surge front and the water surface of the steady flow. Afterwards, the experiments simulating bore wave and steady flow were conducted to study the characteristics of the wave shape and the wave forces on the girder model. As a result, with the same wave height, the wave force of the broken bore wave was larger than that of the un-broken bore wave and with similar inundation depths, the wave force of the broken bore wave (prototype: inundation depth 20m, static water 7.5m, wave height 12.5m) is much greater than that of the steady flow (prototype: inundation depth 17.5m).
